Add missing shapefile creation tests

[larsbutler]

Hi, this patch is a follow-up to https://github.com/gem/openquake-server/pull/18.

Changes:

• updated README dependencies
• fixed a minor bug in bin/gen_shapefile.py
• added two more tests to tests/bin_gen_shapefile_unittest.py

[al-maisan]

Hello Lars,

can you please fix the following test failure (should be an easy one):

$ (export DJANGO_SETTINGS_MODULE="geonode.settings"; export OQ_MTAPI_DB="mtapi_test"; export OQ_MTAPI_PASSWORD="_Bloujqueewjack9"; nosetests -s tests/*_unittest.py)
............F.................................
======================================================================
FAIL: If no 'output' parameter is specified, create_shapefile() will try to
----------------------------------------------------------------------
Traceback (most recent call last):
File "/p/work/oqsrv/tests/bin_gen_shapefile_unittest.py", line 380, in test_create_shapefile_with_no_output_specified
self.assertEqual(expected_output, config['output'])
AssertionError: '/tmp/shapefiles' != '/tmp/hazard-shapefiles'

[al-maisan]

LGTM